Our experimental clinical investigations suggest that new bone formation will extend bone perimeters when adjacent connective tissue is subjected to tension and functional forces are transmitted beyond the bone margins. This proposal is based on the concept that neuromuscular activity produces biophysical stimuli and that these stimuli influence the differentiation of cells and results in bone formation. The experimental model is the rhesus monkey in which symmetric forces acting on the parietal bones are caused to become asymmetric by detachment of the right temporal muscle. The investigation will examine the effects of this functional imbalance in 1) bone margins, 2) morphology of the sagittal suture, 3) the normal and detached muscle, and 4) the skeletal and muscle function. The effects on level and pattern of muscle activity will be studied by EMG and histologic methods will be employed for examination of the morphologic findings.